Update Terraform icon

[radeksimko]

This updates the icon to the latest version as per brand guidelines https://www.hashicorp.com/brand#terraform It doesn't exactly match the guidelines in terms of the exact shade of purple, but respecting the rest of the ecosystem, as per Contributing guidelines also seems important

While, you can add additional colors to styles/ui-variable.less, but please do not do this unless you find it absolutely necessary.

• predefined purple is #a074c4
• Terraform logo would be #7B42BC

Let me know if you'd be willing to accept that change of purple shade and I can update it as well.

As for the shape there was a minor change in spacing between the segments.

Before vs After

Top 2 icons are before, bottom 2 are after.

VS Code

Atom

[orta]

This looks like a good improvement to me!

I don't think we want to change the colors because that could affect a bunch of other vscode ecosystem things though 👍🏻